The Hirose DF17(4.0)-30DP-0.5V(57) is a 30-position, dual-row header from the DF17 series, using a 0.020" (0.50mm) pitch. It supports mated stacking heights of 7mm and 8mm, which means the board-to-board spacing is fixed to one of those two values — no field adjustment, no spacer. This is a mezzanine interconnect for parallel PCB stacking where the z-height budget is known before layout.
Stack height choice — 7 mm or 8 mm, not both on the same board
The mated stacking heights are listed as 7mm and 8mm. That is not a range — it means the connector, when mated with the correct DF17 receptacle, produces one of those two board-to-board gaps depending on which receptacle variant is used.
30 positions vs 20, 40, or 50 — the only variable is circuit count
Within the DF17(4.0)-0.5V(57) subfamily, the 30-position variant shares the same 0.020" (0.50mm) pitch, same 0.248" (6.30mm) height above board, same dual-row gold-plated construction, and same board guide / solder retention features as the 20-position (DF17(4.0)-20DP-0.5V(57)), 40-position (DF17(4.0)-40DP-0.5V(57)), and 50-position (DF17(4.0)-50DP-0.5V(57)) siblings. The footprint changes with position count, so a 30-circuit board cannot use a 40-position header even if the pitch matches.
Active production — no last-time-buy pressure on this line
The DF17(4.0)-30DP-0.5V(57) carries an Active product status and is ROHS3 compliant. That means there is no phase-out deadline or last-time-buy window to manage — it can be specified into a new BOM without an obsolescence risk.